Fluid-actuated regulated cushioned hoist.



Not 845,827. Y PATENTED MAR. 5, 1907.` I

G. P. STEEDMAN.

FLUID AGTUATED REGULATED GUSHIONED HOIST. APPLIoATIoN FILED vso.4,19o5.

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' Z'zfwesses: gegrgai'em No. 845,827. PATENTED MAR. 5, 1.907.

' G. P. STEEDMAN.

FLUID ACTUATED REGULATED GUSHIONED HOIST.

APPLICATION FILED BECA, 1905. I

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PTENTED' MAR. 5, 190?.

v G. F. STEBDMAN. FLUID ACTUATED REGULATED GUSHIONED HOIST.

APPLIQATIOH FILED DBO. 4, 1905.

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GEORGE F. STEEDMAN,- OF ST. LOUIS, MISSOURI.

FLUID-ACTUATED REGULATED CUSHIONED HOIST.

Specification of Letters Patent.

r'atentect March. 5, 1907.

Application iled December 4,1905. Serial No. 290181- following is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, forming part ofthis speciication, in which- 4 Figure 1 is a diagrammatical view showing one arrangement of piping, cylinder', and operating-valve in which my invention is employed. Fig. 2 is a vertical longitudinal Sectional view through a cylinder constructed in accordance with my invention. Fig. 3 is a fragmentary view, partly in section and partly in elevation, of a slightly-modified form of the piston-controlled grading device. Fig. 4 is a still Jfurther mcdiiied for-m of the grading device, and Fig. 5 is a mcdiiied form` of a cylinder;

This invention relates to fluid-actuated hoists in which a cylinder is employed for containing a piston to be actuated by a suitable iiuid, preferably air, one of the objects of the invention being to provide means whereby the speed of the stroke of the piston as it nears either end of the cylinder will be .automatically reduced and cushioned in Such a manner that all tendency to jar or undulyvibrate will be avoided. It is desirable to provide a cushion at each end of the cylinder when the piston is adjacent thereto, which cushion is due to the compnession of the airexisting between the end of the cylinder and If the exhaust is suddenly cut ofi, the piston will be brought to a sudden stop, and as a result thereof the load carried by said piston will receive a jar, which in some cases would be injurious to the loadas, for example, 'if glass is being raised or lowered by the piston. Aside from tliis the wear 'and tear on the hoist will be severe,

and if the pressure is great enough the sudden l compression of the air is liable to blow out the cylinder-head. To overcome the objecsition of rest.

As illustrating one form of mechanism` whereby the objects of my invention may be carried out, 1 designates a cylinder, at the respective ends of Which are the cylinder-heads 2 and 3. h Each head is provided with a tube 4, comprlsing a Socket-seat 4EL Vfor the reception of hollow cut-Otis 5, of which there is one on each side of the piston 6 operable in said cylinder. In the form illustrated in Fig. 2 the cut-OIT is hollow and is provided with a'series of perforations -7 in the form of a spiral, and as the piston moves toward the respective ends of the cylinder either of the cut-offs 5 will be'intrcduced into its particular socket-seat 4a. the tube 4 is in communication with an exhaust-pipe 8, communicating with the seat 4a through the recess 9, and the Vcylinder receives its supply through a supply-pipe 10, in communication with the cylinder through the recess 11.

It will beobserved that the cylinder-heads are arranged so as to be interchangeable one for the other. The cylinder-head through which the piston-stem projects is provided with a packing 12, held in place by a gland 13, while the head in the opposite end of the cylinder has its opening 14 closed by a plug 15, which plug may be interchanged for the gland and packing in the opposite head, which gland and packing are in a recess corresponding to the opening 14.

The operation oi' the form illustrated in Figs. 1 and 2 may be described as Jfollows: The arrangement of piping is similar to that illustrated in my prior patent, No. 840,877, dated January 8, 1907, and shown in Fig. 1. The operating-valve 16 may be turned so as to exhaust the motive Huid from the ipe 17 incommunication with the upper enclof the cylinder and which is in communication with The recess formed by the regulating device 18. The -regulating device 18 is preferably of the same construction as that shown in Fig. 5 of the drawings of my patent referred to, so that a detailed description of same is not deemed necessary. The piston will be raised at the maximum speed until the hollow cut-ofi 5 begins to enter the socket-seat 4, through which the fluid has been exhausting. As the end of the hollow cut-OH 5 enters the socket-seat the exhaust will be initially cut offwthat is to say, the iiuid cannot exhaust through the socket-seat 4a to the extent to which it previously exhausted, because the size of the opening will be decreased. In other words,

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as soon as the end of the cut-oil 5 enters the opening surrounded by the free end of the flange 4 the air will be permitted only to pass through the perforations 7. At first the air may pass through all of the perforations; but as the cut-oil' continues to enter the socketseat the perforations will successively bccome closed 011 account of the imperlorate lange 4 until all of the perforations,or practically all of them, will be closed. It will be apparent that as the perforations successively close the volume of the exhaust will decrease, so that while a cushion is formed at the end of the cylinder the stopping of the piston will be gradual and any tendency to unduly vibrate or jar will be avoided.

In order to illustrate one method of assembling the parts, I have shown the construction in Fig. 2 as including a piston-stein 19, having a threaded end projecting' through the respective cut-ofl's and through the piston. l/Vhile this is an inexpensive and convenient manner of assembling the parts; I

would have it understood that I do not wislr to limit myself to this exact arrangement,

- but reserve the right to employ other methods for accomplishing the same result.

In the form illustrated in Fig. 3 the flange 4 is substantially the same in construction as the iiange in Fig. 2. The cut-off, however, is tapered, said cut-off being designated by the reference-numeral 20, the taper thereof being toward the free end. Thus it will be seen that as the cut-off begins .to enter the socket-seat 4a the opening will begin to be restricted until by the time the cut-off is in the position indicated in dotted lines the cylinder Will haVeceased-to exhaust and the piston will be cushioned. l

vIn Fig. 4 I have illustrated a still further modified form of cut-off, which is designated by the reference-numeral 21, and-which consists of a hollow cylinder having a plurality of longitudinally-arranged slots 22 therein, which slots-are. so arranged that as the cutoff moves into the socket-seat the slots will become less exposed, and thereby gradually cut off the exhaust in a manner similar to the operation described as applied to the construction shoWn in Fig. 2.

In Fig. 5 I have illustrated the cut-off as being on the outside of the cylinder at the end thereof, and it is obvious that this form may be employed without materially departing from the spirit of the invention.1 By so constructing the device that the cut-off is on the outside a saving of material is effected, because it willnot require as much material to form the cylinder. Therefore I do not limit my invention to a cut-oil'1 on the inside of the cylinder.

In describing the above invention I have referred to the cylinder as being of the .`vertical type, in which the piston has an ascending and descending movement. How-l ever, I reserve the right to arrange the cylinder horizontal] or at an other angle and D 5 wherever the terms vert1cal, top, or

bottom, ascending, or descending,

let and outlet openings in the cylinder-heads,

a piston in the cylinder, a piston-stem'projecting through one of the central openings, a plug in the other cylinder-opening, and means carried by the piston for cutting ofll communication between the outlet-openings and the cylinder; substantially as described.

2. In a device of the class described, the combination with a cylinder provided with heads having inlet and outlet openings, flanges formed integral with the respective heads of the cylindei` yand forming socketseats which'communicate with the exhaustopenings in the heads of the cylinder, said flanges being spaced away from the side walls of the cylinder, a piston in the cylinder, and hollow cut-offs carried by the piston and having openings in the walls thereof and insertible in the socket-seats whereby communication between the socket-seats and cylinder may be had only through the 'walls of the cut-off, substantially as described.

3. In a device of the class described, the combination with a cylinder having inletopenings, a hollow member at each end of the cylinder and communicating with an exhaust-opening in the end of the cylinder and spaced away from the side walls of the cylinder, a piston, concentric cut-offs carried by the piston and movable thereby into said hollow members whereby communication may be cut off between the exhaust and the cylinder substantially as described.

4. A device of the class described, comprising a cylinder having inlet and outlet openings, a source of supply, tubes connected to the source of supply and to the inlet-openings, a piston operating in the cylinder, and an exhaust cut-off carried by the piston, in combination with means for controlling the admission and exhaust of the motive iiuid to and from the cylinder; substantially as described.

In testimony whereof ,I hereunto aflix my Signature, in the presence of two witnesses, this 21st day of November, 1905.

GEORGE F. STEEDMAN.

Witnesses:

HARRY A. HEPER, T. R. CLARKSON.

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